1. Field of the Invention
The purpose of this invention is to manufacture complex shaped Cr.sub.3 C.sub.2 /Al.sub.2 O.sub.3 components by an injection molding technique. Pressureless sintering or vacuum sintering is performed on the unsintered or green products to manufacture ceramic complex shaped components.
2. Cross-Reference to Related Application
Alumina has good physical and chemical properties and is currently the most widely used material for ceramics. But its inherent brittleness had lowered its dependability. In recent years, ceramic researchers had kept on improving its dependability. For example, a second phase strengthener can be added into the alumina base material which can greatly increase its toughness and improve its dependability. A second phase strengthner can include high hardness grains, bearded crystal, or plate grains. But recent research indicates that bearded crystal can cause cancer while plate grains have directional properties which should be considered and are not easy to process. Not only do the Cr.sub.3 C.sub.2 /Al.sub.2 O.sub.3 grain strengtheners overcome the above drawbacks but they are also far more convenient and economical to process in comparison with the bearded crystal or plate grains.
Since the molded shape of structural ceramic was restricted and there was no way to expand scope of its application, the application of injection molding techniques can lower the cost of the molded shape, can make mass production possible, and can produce complex-shaped and high precision products. Thus, a vacuum and pressureless sintering process and injection molding were used in this disclosure to manufacture commercial precision ceramic components.
Adding chromium carbide in the alumina base can improve the alumina's inherent brittleness and improve its dependability. There is also no transformation in the interface of Cr.sub.3 C.sub.2 /Al.sub.2 O.sub.3, and the addition of chromium carbide can simultaneously increase the strength and toughness of the resulting material, which is seldom seen in composite materials.